Algeria's Olympic 1500m gold medallist Taoufik Makhloufi on Thursday withdrew from next month's world championships in Russia because of a viral infection, El Watan newspaper reported on its website.
The 25-year-old had a difficult start to his outdoor season, finishing 11th over a mile at Eugene, Oregon, on June 1.
He has not trained for the past month.
Makhloufi endured a controversial London Olympics when he was disqualified for not trying hard enough in his 800m heat before being reinstated to race the 1500m.
He is the latest big name to miss the world championships, which take place in Moscow from August 10-18.
Kenya's world and Olympic 800m champion David Rudisha has already been ruled out with a knee injury while Jamaican 100m champion Yohan Blake has withdrawn with a hamstring problem.
Meanwhile, sprinters Tyson Gay and Asafa Powell have been ruled out after failing drug tests.